JP-A-5-282665 discloses a surface finishing device for magnetic media in which the aluminum surface of a rotary body is brought into contact with the magnetic coating. Arranged between the unwinding reel and the winding-up reel is an air damper for regulating the tape tension and a blade device for removing projections from the surface of the coating. After this, the rotary body comes into action for cleaning and smoothing the partially destroyed coating surface.
EP-A-709 832 discloses a further surface finishing device for individual magnetic tapes, in which the magnetic tape is pressed by means of an air stream against a lapping band of a lapping device and projections and deposits are removed from the magnetic coating. In this case, the tape tension is measured either before or after the lapping device as a reference value for the respective tape tension after or before the lapping device and the flow of the air stream device is controlled such that both tape tensions are optimized, so that dropouts during magnetic tape recording/playback are eliminated. These controlling and regulating operations are carried out independently of mechanical parameters of the magnetic tape.